1. Field of the Invention
The present invention relates to a catalyst for decomposing ammonia contained in waste gases to nitrogen and a method of using the same for ammonia decomposition.
2. Description of the Related Art
Ammonia is widely used as a starting material for fertilizers and nitric acid as well as a reducing agent for removal of nitrogen oxides (NOx) in coolants and exhaust gases. As a result, a large amount of ammonia is emitted from various chemical plants, industrial waste disposal facilities for such things as refrigerators, and combustion exhaust gas treatment facilities.
Ammonia is a gas having a characteristic irritating odor, and should be emitted into the atmosphere as little as possible. In reality, however, the formation of ammonia by degradation of organisms, emission of ammonia from coolants in disposed machines, and emission of unreacted ammonia in the reduction process of nitrogen oxides in flue gases result in the release of large amounts of ammonia into the atmosphere.
As a method for preventing ammonia from being emitted into the atmosphere, the decomposition of ammonia into nitrogen, which is harmless, is known utilizing a catalyst of iron oxide or nickel oxide held on a carrier such as an alumina or silica-alumina carrier, by which the reaction is effected according to the reaction equation shown below.2NH3+3/2O2→N2+3H2O 
However, when using a conventional catalyst NO, NO2 and N2O are generated as a result of the side reactions shown below and cause the another problem of air pollution.2NH3+5/2O2→2NO+3H2O 2NH3+7/2O2→2NO2+3H2O 2NH3+O2→N2O+3H2O 